CN107077947B

CN107077947B - Power inductor

Info

Publication number: CN107077947B
Application number: CN201580042687.8A
Authority: CN
Inventors: 朴寅吉; 卢泰亨; 金炅泰; 赵承勋; 郑俊镐; 南基正; 李政圭
Original assignee: Moda Innochips Co Ltd
Current assignee: Moda Innochips Co Ltd
Priority date: 2014-08-07
Filing date: 2015-06-01
Publication date: 2020-02-28
Anticipated expiration: 2035-06-01
Also published as: CN107077947A; EP3179489B1; TWI590271B; JP2017524256A; US10541075B2; KR20160019042A; KR101718343B1; US20170236632A1; JP6441452B2; TWI614776B; JP2017524255A; EP3179490A1; EP3179489A4; EP3179489A1; CN106663518A; EP3179490A4; KR20160018382A; KR101686989B1; TW201611052A; JP6408688B2

Abstract

The present invention provides a power inductor, comprising: a body, at least one substrate disposed inside the body, at least one coil pattern disposed on at least one surface of the substrate, and an insulating layer formed between the coil pattern and the body, wherein the insulating layer is formed of parylene.

Description

Power inductor

Technical Field

The present disclosure relates to a power inductor, and more particularly, to a power inductor having excellent Inductance (Inductance) characteristics as well as improved insulation characteristics and thermal stability.

Background

The power inductor is typically provided to a power circuit, such as a DC-DC converter in a portable device. Such power inductors are widely used to replace the typical wound Choke Coil (hook Coil) when the power circuit is operating at higher frequencies and is miniaturized. Further, as portable devices become smaller and multifunctional, power inductors are being developed in a trend toward miniaturization and high current and low resistance.

Power inductors may be fabricated in the form of laminates in which ceramic sheets containing a plurality of ferrites (ferrites) or dielectrics are laminated, the dielectrics having a small dielectric constant. Here, a metal pattern is formed on the ceramic sheet in a coil pattern shape. The coil patterns formed on each of the ceramic sheets are connected by conductive vias formed on each ceramic sheet, and may define an overlapping structure along a vertical direction in which the sheets are laminated. In general, the main body constituting this power inductor has been conventionally manufactured by using a ferrite material of a quaternary system including nickel (Ni) -zinc (Zn) -copper (Cu) -iron (Fe).

However, the saturation magnetization value of ferrite materials is lower than that of metal materials, so that high current characteristics required for modern portable devices are not achievable. Therefore, the main body constituting the power inductor is manufactured by using the metal powder, so that the saturation magnetization value can be relatively increased as compared with the case where the main body is manufactured with a ferrite material. However, when the body is manufactured by using metal, a problem of an increase in material loss may occur because eddy current at a high frequency and a loss of hysteresis increase. To reduce this material loss, a structure is used in which the metal powder therebetween is insulated by a polymer.

However, the power inductor having a body manufactured by using metal powder as well as polymer has a problem in that the inductance decreases as the temperature increases. That is, the temperature of the power inductor increases due to heat generated from the portable device to which the power inductor is applied. Therefore, a problem in that the inductance decreases as the metal powder constituting the main body of the power inductor is heated may occur.

Also, in the power inductor, the coil pattern may contact the metal powder inside the body. To prevent this contact, the coil pattern and the body should be insulated from each other.

(prior art document)

(patent document)

Korean patent laid-open No. 2007-0032259

Disclosure of Invention

Problems to be solved by the invention

The present disclosure provides a power inductor in which temperature stability is improved through heat dissipation in a main body so that reduction of inductance can be prevented.

The present disclosure also provides a power inductor capable of improving insulation characteristics between a coil pattern and a body.

The present disclosure also provides a power inductor capable of improving capacity and permeability.

Means for solving the problems

According to an exemplary embodiment, a power inductor includes a body, at least one substrate disposed inside the body, at least one coil pattern disposed on at least one surface of the substrate, and an insulating layer formed between the coil pattern and the body, wherein the insulating layer is formed of parylene.

The body may include a metal powder, a polymer, and a thermally conductive filler.

The metal powder may comprise a metal alloy powder containing iron.

The metal powder may have a surface coated with at least one of a ferrite material and an insulator.

The insulator may be parylene coated in a thickness of approximately 1 μm to approximately 10 μm.

The thermally conductive filler may include one or more selected from the group consisting of MgO, AlN, and a carbon-based material.

The thermally conductive filler may be included in an amount of approximately 0.5 wt% to approximately 3 wt% with respect to 100 wt% of the metal powder, and have a size of approximately 0.5 μm to approximately 100 μm.

The substrate may be formed of a copper clad laminate, or formed such that copper foils are attached to both surfaces of a metal plate containing iron.

The insulating layer may be coated such that parylene is vaporized and coated on the coil pattern with a uniform thickness.

The insulating layer may be formed in a thickness of approximately 3 μm to approximately 100 μm.

The power inductor may further include an external electrode formed outside the body and connected to the coil pattern.

The substrate may be disposed at least in duplicate, and the coil pattern may be formed on each of the at least two or more substrates.

The power inductor may further include a connection electrode disposed outside the body and provided to connect the at least two or more coil patterns.

The power inductor may further include at least two or more external electrodes respectively connected to the at least two or more coil patterns and formed outside the body.

The plurality of external electrodes may be formed on the same side surface of the body to be spaced apart from each other, or formed on different side surfaces of the body from each other.

The power inductor may further include a magnetic layer disposed in at least one region of the body, and a magnetic permeability of the magnetic layer is greater than a magnetic permeability of the body

The magnetic layer may be formed to include a thermally conductive filler.

Advantageous effects

In the power inductor of the present invention, the main body includes the metal powder, the polymer, and the heat conductive filler, and heat can be dissipated to the outside by including the heat conductive filler, so that reduction of inductance can be prevented.

The insulating layer may be formed on the coil pattern in a uniform thickness by coating with parylene (parylene), and the insulating property may be improved compared to other materials.

The power inductor of the present invention can improve the permeability of the power inductor by providing the body with at least one magnetic layer.

The body includes at least two or more substrates having coil patterns respectively formed on at least one surface thereof so that a plurality of coils can be formed in one body. Thus, the capacity of the power inductor may be increased.

Drawings

Fig. 1 is a perspective view of a power inductor according to a first exemplary embodiment.

Fig. 2 is a sectional view taken along line a-a' of fig. 1.

Fig. 3 to 5 are sectional views of a power inductor according to a second exemplary embodiment.

Fig. 6 is a perspective view of a power inductor according to a third exemplary embodiment.

Fig. 7 and 8 are cross-sectional views taken along lines a-a 'and B-B' of fig. 6, respectively.

Fig. 9 is a perspective view of a power inductor according to a fourth exemplary embodiment.

Fig. 10 and 11 are cross-sectional views taken along lines a-a 'and B-B' of fig. 9, respectively.

Fig. 12 is a perspective view of a power inductor according to a modified exemplary embodiment of the fourth exemplary embodiment.

Fig. 13 to 15 are sectional views sequentially illustrating a method of manufacturing a power inductor according to an exemplary embodiment.

Fig. 16 and 17 are sectional images of a power inductor according to comparative examples and exemplary embodiments.

Detailed Description

Hereinafter, embodiments will be described in more detail with reference to the accompanying drawings. This summary may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

Fig. 1 is a perspective view of a power inductor according to an exemplary embodiment, and fig. 2 is a sectional view taken along line a-a' of fig. 1.

Referring to fig. 1 and 2, the power inductor according to the first exemplary embodiment may include a body 100 having a thermally conductive filler 130, a substrate 200 disposed in the body 100, a

coil pattern

310, 320, 300 formed on at least one surface of the substrate 200, and an

external electrode

410, 420, 400 disposed outside the body 100. Also, the insulating layer 500 may be further included on the

coil patterns

310 and 320.

The body 100 may have a hexahedral shape. However, the body 100 may have a polyhedral shape other than a hexahedral shape. The body 100 may include a metal powder 110, a polymer 120, and a thermally conductive filler 130. The metal powder 110 may have an average particle diameter of approximately 1 μm to approximately 50 μm. Also, one kind of particles or two or more kinds of particles having the same size may be used as the metal powder 110. In addition, one kind of particles or two or more kinds of particles having a plurality of sizes may also be used as the metal powder. For example, a mixture of first metal particles having an average size of approximately 30 μm and second metal particles having an average size of approximately 3 μm may be used. When two or more kinds of metal powders 110 different from each other are used, the capacity can be maximally implemented because the filling rate of the body 100 can be increased. For example, when 30 μm metal powder is used, gaps may be generated between the 30 μm metal powder, and therefore, the filling rate must be reduced. However, the filling rate can be increased by using a 3 μm metal powder mixed with a 30 μm metal powder. A metal material containing iron (Fe) may be used for the metal powder 110. For example, one or more types of metals selected from the group consisting of: iron-nickel (Fe-Ni), iron-nickel-silicon (Fe-Ni-Si), iron-aluminum-silicon (Fe-Al-Si), and iron-aluminum-chromium (Fe-Al-Cr). That is, the metal powder 110 may be made of a material having a ferrimagnetic structure or magnetic propertiesThe metal alloy is formed and has a predetermined magnetic permeability. Also, the metal powder 110 may have a surface coated with a ferrite material, and may be coated with a material having a different magnetic permeability from the metal powder 110. For example, the ferrite material may be formed of a metal oxide ferrite material, and one or more oxide ferrite materials selected from the group consisting of: nickel oxide ferrite materials, zinc oxide ferrite materials, copper oxide ferrite materials, manganese oxide ferrite materials, cobalt oxide ferrite materials, barium oxide ferrite materials, and nickel-zinc-copper oxide ferrite materials. That is, the ferrite material coated on the surface of the metal powder 110 may be formed of a metal oxide containing iron, and its magnetic permeability may be greater than that of the metal powder 110. Since the metal powders 110 are magnetic, if the metal powders 110 are in contact with each other, a short circuit due to insulation breakdown may occur. Thus, the surface of the metal powder 110 may be coated with at least one insulator. For example, although the surface of the metal powder 110 may be coated with an oxide or an insulating polymer material, it may be preferably coated with parylene. Parylene may be coated at a thickness of approximately 1 μm to approximately 10 μm. Here, when parylene is formed in a thickness less than approximately 1 μm, the insulating effect of the metal powder 110 may be reduced, and when parylene is formed in a thickness greater than approximately 10 μm, the size of the metal powder 110 is increased, the distribution of the metal powder 110 in the body 100 is reduced, and thus, magnetic permeability may be reduced. Also, the surface of the metal powder 110 may be coated with various insulating polymer materials other than parylene. The oxide of the coating metal powder 110 may be formed by oxidizing the metal powder 110, and alternatively, selected from TiO₂、SiO₂、ZrO₂、SnO₂、NiO、ZnO、CuO、CoO、MnO、MgO、Al₂O₃、Cr₂O₃、Fe₂O₃、B₂O₃And Bi₂O₃May be coated on the metal powder. Here, the metal powder 110 may be coated with an oxide having a double structure, or coated with a double structure of an oxide and a polymer material. Of course, the surface of the metal powder 110 may be ferriteThe bulk material is coated with an insulator. The surface of the metal powder 110 is thus coated with an insulator, so that short circuits caused by contact between the metal powders 110 can be prevented. Here, even when the metal powder 110 is coated with an oxide, an insulating polymer material, or the like, or double-coated with a ferrite and an insulator, the metal powder may be coated in a thickness of approximately 1 μm to approximately 10 μm. The polymer 120 may be mixed with the metal powders 110 to insulate the metal powders 110 from each other. That is, although the metal powder 110 may have a limitation in that the material loss increases due to the eddy current loss at high frequency and the hysteresis loss increases, the polymer 120 may be included to reduce the material loss and insulate the metal powders 110 from each other. The Polymer 120 may comprise one or more polymers selected from the group consisting of epoxy, polyimide, and Liquid Crystal Polymer (LCP). Also, the polymer 120 may be formed of a thermoplastic resin that provides insulation between the metal powders 110. As the thermoplastic resin, one or more selected from the group consisting of: novolac Epoxy resins (Novolac Epoxy resins), Phenoxy Type Epoxy resins (Phenoxy Type Epoxy resins), diphenol propane Type Epoxy resins (BPAType Epoxy resins), bisphenol Type Epoxy resins (BPF Type Epoxy resins), Hydrogenated diphenol propane Epoxy resins (Hydrogenated BPA Epoxy resins), Dimer acid Modified Epoxy resins (Dimer acid Modified Epoxy resins), Urethane Modified heat generating Epoxy resins (unreacted Modified Epoxy resins), Rubber Modified Epoxy resins (Rubber Modified Epoxy resins), and dicyclopentadiene Type diene Epoxy resins (DCPD Type Epoxy resins). Here, the polymer 120 may be included in an amount of approximately 2.0 wt% to approximately 5.0 wt% with respect to 100 wt% of the metal powder. However, when the amount of the polymer 120 is increased, the volume fraction of the metal powder 110 is decreased, and there may be a limitation because the magnetic permeability of the body 100 may be decreased. Also, when the amount of the polymer 120 is reduced, there may be a limitation in that inductance characteristics may be reduced due to inward permeation of a strong acid solution, a strong alkali solution, or the like used in manufacturing the inductor. Therefore, the polymer 120 may be included in a range that does not reduce the saturation magnetization value and inductance of the metal powder 110In the enclosure. Also, the thermally conductive filler 130 is included to solve the limitation that the body 100 is heated by external heat. That is, the metal powder 110 in the body 100 is heated by external heat, but the heat of the metal powder 110 may be dissipated to the outside by including the thermally conductive filler 130. The thermally conductive filler 130 may include one or more selected from the group consisting of MgO, AlN, and a carbon-based material. Here, the carbon-based material may include carbon and have various shapes. For example, graphite, carbon black, graphene, graphite, or the like may be included. Also, the thermally conductive filler 130 may be included in an amount of approximately 0.5 wt% to approximately 3 wt% with respect to 100 wt% of the metal powder 110. When the amount of the thermally conductive filler 130 is less than the above range, a heat dissipation effect may not be achieved, and when the amount is greater than the above range, the magnetic permeability of the metal powder 110 may be reduced. Also, the thermally conductive filler 130 may have a size of approximately 0.5 μm to approximately 100 μm. That is, the thermally conductive filler 130 may have a size greater than or less than the metal powder 110. The body 100 may be manufactured by laminating a plurality of sheets formed of a material including the metal powder 110, the polymer 120, and the thermally conductive filler 130. Here, when the body 100 is manufactured by laminating a plurality of sheets, the contained amount of the thermally conductive filler 130 may be different for each sheet. For example, the amount of thermally conductive filler 130 in the sheet may gradually increase upward or downward away from the substrate 200. Also, the body 100 may be formed by printing a paste formed of a material including the metal powder 110, the polymer 120, and the thermally conductive filler 130 in a predetermined thickness. Alternatively, the body 100 may be formed through various methods as necessary, such as a method whereby this paste is put into shape and pressed. Here, the number of sheets laminated to form the body or the thickness of the paste printed at a predetermined thickness may be determined as an appropriate number or thickness in consideration of electrical characteristics, such as inductance required for the power inductor.

The substrate 200 may be disposed inside the body 100. At least one or more substrates 200 may be provided. For example, the substrate 200 may be disposed inside the body 100 along a longitudinal direction of the body 100. Here, one or more substrates 200 may be provided. For example, the two substrates 200 may be disposed to be spaced apart from each other at a predetermined interval in a direction perpendicular to a direction in which the external electrodes 400 are formed. The substrate 200 may be formed of a Copper Clad Laminate (CCL) or a metal ferrite material. Here, the substrate 200 is formed of a metal ferrite material so that magnetic permeability can be increased and capacity can be easily realized. That is, the CCL is manufactured by attaching a copper foil (foil) to glass-reinforced elastic fiber. However, since the CCL does not have permeability, the permeability of the power conductor may be reduced thereby. However, when a metal ferrite material is used as the substrate 200, the magnetic permeability of the power inductor may not be reduced because the metal ferrite material has magnetic permeability. This substrate 200 using the metal ferrite material may be manufactured by attaching a copper foil to a plate having a predetermined thickness and formed of a metal containing iron, for example, one or more metals selected from the group consisting of iron-nickel (Fe-Ni), iron-nickel-silicon (Fe-Ni-Si), iron-aluminum-silicon (Fe-Al-Si), and iron-aluminum-chromium (Fe-Al-Cr). That is, an alloy formed of at least one metal including iron is manufactured in a plate shape having a predetermined thickness. Then, a copper foil is attached to at least one surface of the metal plate, and thus, the substrate 200 may be manufactured. Also, at least one conductive via hole (not shown) may be provided in a predetermined region of the substrate 200, and the

coil patterns

310 and 320 respectively disposed in the upper and lower sides of the substrate 200 may be electrically connected through the conductive via hole. The conductive via hole may be provided through a method of forming a via hole (not shown) through a substrate in a thickness direction in the substrate 200 and then filling a conductive paste into the via hole.

The

coil patterns

310, 320, 300 may be disposed on at least one surface of the substrate 200, and preferably on both surfaces of the substrate. This

coil pattern

310, 320 may be formed in a spiral shape in a direction from a predetermined region of the substrate 200, for example, from the central portion to the outside, and one coil may be defined in such a manner that the two

coil patterns

310, 320 formed on the substrate 200 are connected. Here, the upper coil pattern 310 and the lower coil pattern 320 may be formed in the same shape as each other. Also, the

coil patterns

310, 320 may be formed to overlap each other, and the coil pattern 320 may be formed to overlap an area on which no coil pattern 310 is formed. The

coil patterns

310 and 320 may be electrically connected through conductive vias formed on the substrate 200. The

coil patterns

310, 320 may be formed through a method such as thick film printing, diffusion, deposition, plating, or sputtering. The

coil patterns

310 and 320 and the conductive via holes may be formed of a material including at least one of silver (Ag), copper (Cu), and a copper alloy. Meanwhile, when the

coil patterns

310 and 320 are formed through an electroplating process, a metal layer, such as a copper layer, may be formed on the substrate 200 through an electroplating process and patterned through a photolithography process. That is, the

coil patterns

310, 320 may be formed on the surface of the substrate 200 by forming a copper layer on a seed layer through an electroplating process and patterning the layer. Of course, the

coil patterns

310 and 320 having the predetermined shapes may also be formed as follows: a photosensitive film pattern having a predetermined shape is formed on the substrate 200, then a metal layer is grown from the exposed surface of the substrate 200 by performing an electroplating process, and then the photosensitive film is removed. The

coil patterns

310, 320 may also be formed in multiple layers. That is, a plurality of coil patterns may be further formed above the coil pattern 310 formed above the substrate 200, and a plurality of coil patterns may be further formed below the coil pattern 320 formed below the substrate 200. When the

coil patterns

310, 320 are formed in multiple layers, an insulating layer is formed between upper and lower layers, and conductive vias (not shown) are formed in the insulating layer, and thus, the multiple layers of coil patterns may be connected.

The

external electrodes

410, 420, 400 may be formed at both end portions of the body 100. For example, the external electrode 400 may be formed on two side surfaces facing each other in the longitudinal direction of the body 100. This external electrode 400 may be electrically connected to the

coil patterns

310, 320 of the body 100. That is, at least one end portion of the

coil patterns

310, 320 is exposed to the outside of the body 100, and the external electrode 400 may be formed so as to be connected to the end portion of the

coil patterns

310, 320. This external electrode 400 may be formed such that the body 100 is dipped into a conductive paste or at both ends of the body 100 via various methods such as printing, deposition, or sputtering. The external electrode 400 may be formed of a metal having conductivity. For example, one or more metals selected from the group consisting of gold, silver, platinum, copper, nickel, palladium, and alloys thereof. Also, a nickel plating layer (not shown) or a tin plating layer (not shown) may be further formed on the surface of the external electrode 400.

An insulating layer 500 may be formed between the

coil patterns

310 and 320 and the body 100 to insulate the

coil patterns

310 and 320 from the metal powder 110. That is, the insulating layer 500 may be formed on the upper and lower portions of the substrate 200 to cover the

coil patterns

310, 320. This insulating layer 500 may be formed such that parylene is coated on the

coil patterns

310, 320. For example, parylene may be deposited on the

coil patterns

310, 320 by providing the substrate 200 with the

coil patterns

310, 320 formed thereon inside the deposition chamber and then vaporizing parylene and supplying the vaporized parylene into the vacuum chamber. For example, a first heating process of parylene is first heated and vaporized in a Vaporizer (Vaporizer) to be converted into a dimer (dimer) state as in [ formula 1], and then a second heating process is heated and thermally decomposed into a Monomer (Monomer) state as in [ formula 2 ]. When the parylene is then cooled by using a Cold Trap (Cold Trap) provided to be connected to the decomposition chamber and a Mechanical vacuum Pump (Mechanical vacuum Pump), the parylene is converted from a monomer state to a polymer state as in [ formula 3] and deposited on the

coil patterns

310, 320. Of course, the insulating layer 500 may be formed of an insulating polymer other than parylene, for example, one or more materials selected from epoxy, polyimide, and liquid crystal polymer. However, the insulating layer 500 may be formed on the

coil patterns

310, 320 in a uniform thickness by coating with parylene, and even when formed in a small thickness, the insulating property may be improved compared to other materials. That is, when parylene is coated as the insulating layer 500, the insulating property can be improved by increasing the breakdown voltage, although the insulating layer is formed in a smaller thickness than polyimide is formed. Also, the insulating layer may be formed in a uniform thickness by filling gaps between the patterns according to a distance between the

coil patterns

310, 320, or may be formed in a uniform thickness along steps in the patterns. That is, when the distance between the

coil patterns

310, 320 is excessively large, parylene may be coated in a uniform thickness along steps in the pattern. Also, when the distance between the

coil patterns

310 and 320 is small, parylene may be formed on the coil patterns at a predetermined thickness by filling gaps between the patterns. Here, the insulating layer 500 may be formed in a thickness of approximately 3 μm to approximately 100 μm by using parylene. When parylene is formed with a thickness less than approximately 3 μm, the insulating property may be reduced. Also, when parylene is formed in a thickness greater than approximately 100 μm, the thickness occupied by the insulating layer 500 within the same size increases, the volume of the body 100 becomes small, and thus, the magnetic permeability may be reduced. Of course, the insulating layer 500 may be formed on the

coil patterns

310, 320 after being formed of a sheet having a predetermined thickness.

(formula 1)

(formula 2)

(formula 3)

As described above, the power inductor according to the first exemplary embodiment may improve the insulation characteristic even though the insulation layer 500 is formed in a small thickness by forming the insulation layer 500 between the

coil patterns

310, 320 and the body 100 using parylene. Also, the body 100 is manufactured to include the thermally conductive filler 130 and the metal powder 110 and the polymer 120 so that heat of the body 100 generated by heating the metal powder 110 may be dissipated to the outside. Accordingly, the temperature increase in the main body 100 can be prevented, and thus a limitation such as a reduction in inductance can be prevented. Also, the substrate 200 inside the body 100 may be formed of a metal ferrite material to prevent a decrease in magnetic permeability of the power inductor.

Fig. 3 is a perspective view of a power inductor according to a second exemplary embodiment.

Referring to fig. 3, the power inductor according to the second exemplary embodiment may include a body 100 having a thermally conductive filler 130, a substrate 200 disposed in the body 100,

coil patterns

310, 320 formed on at least one surface of the substrate 200,

external electrodes

410, 420 disposed outside the body 100, an insulating layer 500 disposed on the

coil patterns

310, 320, respectively, and at least one

magnetic layer

600, 610, 620 disposed above and below the body 100, respectively. That is, an exemplary embodiment may further include the magnetic layer 600 to implement another exemplary embodiment. This second exemplary embodiment is mainly described below with respect to a configuration different from that of the first exemplary embodiment.

The

magnetic layers

600, 610, 620 may be disposed in at least one region of the body 100. That is, the first magnetic layer 610 may be formed on an upper surface of the body 100, and the second magnetic layer 620 may be formed on a lower surface of the body 100. Here, the first and second

magnetic layers

610 and 620 are provided to increase magnetic permeability of the body 100, and may be formed of a material having magnetic permeability greater than that of the body 100. For example, the body 100 may be provided to have a magnetic permeability of approximately 20, and the first and second

magnetic layers

610 and 620 may be provided to have a magnetic permeability of approximately 40 to approximately 1000. The first and second

magnetic layers

610 and 620 may be manufactured by using ferrite powder and polymer. That is, the first and second

magnetic layers

610 and 620 may be formed of a material having a magnetic permeability greater than that of the ferrite material of the body 100 so as to have a magnetic permeability greater than that of the body 100, or formed to have a greater content of the ferrite material. Here, the polymer may be included in an amount of approximately 15 wt% with respect to 100 wt% of the metal powder. Also, one or more selected from the group consisting of nickel Ferrite (Ni Ferrite), zinc Ferrite (ZnFerrite), copper Ferrite (Cu Ferrite), manganese Ferrite (Mn Ferrite), cobalt Ferrite (Co Ferrite), barium Ferrite (Ba Ferrite), and nickel-zinc-copper Ferrite (Ni-Zn-Cu Ferrite) or one or more oxide ferrites thereof may be used as the Ferrite powder. That is, the magnetic layer 600 may be formed by using metal alloy powder containing iron or metal alloy oxide containing iron. The ferrite powder can be formed by coating a metal alloy powder with ferrite. For example, the ferrite powder may be formed by coating an iron-containing metal alloy powder with one or more oxide ferrite materials selected from the group consisting of: nickel oxide ferrite materials, zinc oxide ferrite materials, copper oxide ferrite materials, manganese oxide ferrite materials, cobalt oxide ferrite materials, barium oxide ferrite materials, and nickel-zinc-copper oxide ferrite materials. That is, the ferrite powder may be formed by coating the metal alloy powder with a metal oxide containing iron. Of course, the ferrite powder may be formed by mixing a metal powder containing iron with one or more oxide ferrite materials selected from the group consisting of: nickel oxide ferrite materials, zinc oxide ferrite materials, copper oxide ferrite materials, manganese oxide ferrite materials, cobalt oxide ferrite materials, barium oxide ferrite materials, and nickel-zinc-copper oxide ferrite materials. That is, the ferrite powder may be formed by mixing the metal alloy powder with the metal oxide containing iron. The first and second

magnetic layers

610 and 620 may be formed to further include a thermally conductive filler and metal powder and a polymer. The thermally conductive filler may be included in an amount of approximately 0.5 wt% to approximately 3 wt% with respect to 100 wt% of the metal powder. The first and second

magnetic layers

610 and 620 may be formed in a sheet shape and disposed above and below the body 100, respectively. Also, after the body 100 is formed of a material including the metal powder 110, the polymer 120, and the heat conductive filler 130 in a predetermined thickness or formed by insert-molding the paste and pressing the paste, the

magnetic layers

610, 620 may be formed above and below the body 100, respectively. Of course, the

magnetic layers

610, 620 may also be formed by using a paste, and the

magnetic layers

610, 620 may be formed by applying a magnetic material above and below the body 100.

As illustrated in fig. 4, the power inductor according to the second exemplary embodiment may further include third and fourth

magnetic layers

630 and 640 in upper and lower portions between the body 100 and the substrate 200, and as described in fig. 5, fifth and sixth magnetic layers 650 and 660 may further be included therebetween. That is, at least one magnetic layer 600 may be included in the body 100. This magnetic layer 600 may be formed in a sheet shape and disposed in the body 100. That is, at least one magnetic layer 600 may be disposed between a plurality of sheets for manufacturing the body 100. Also, when the body 100 is formed of a material including the metal powder 110, the polymer 120, and the thermally conductive filler 130 at a predetermined thickness, the magnetic layer may be formed during printing. Also, when the body is formed by filling and molding a paste and pressing the paste, the magnetic layer may be input and pressed therebetween. Of course, the magnetic layer 600 may also be formed by using a paste. The magnetic layer 600 may be formed in the body 100 by applying a soft magnetic material when printing the body 100.

As described above, the power inductor according to another exemplary embodiment may improve magnetic permeability of the power inductor by providing the body 100 with at least one magnetic layer 600.

Fig. 6 is a perspective view of a power inductor according to a third exemplary embodiment, fig. 7 is a sectional view taken along line a-a 'of fig. 6, and fig. 8 is a sectional view taken along line B-B' of fig. 6.

Referring to fig. 6 to 8, a power inductor according to a third exemplary embodiment may include: a main body 100; at least two or

more substrates

210, 220, 200 disposed inside the body 100; a

coil pattern

310, 320, 330, 340, 300 formed on at least one surface of each of the two or more substrates 200;

external electrodes

410, 420 disposed outside the body 100; an insulating layer 500 formed on the coil pattern 300; and a connection electrode 700 disposed outside the body 100 to be spaced apart from the

external electrodes

410, 420 and connected to at least one coil pattern 300 formed on each of at least two or more substrates 200 inside the body 100. Hereinafter, a description overlapping with one exemplary embodiment and another exemplary embodiment will not be provided.

At least two or

more substrates

210, 220, 200 may be disposed inside the body 100. For example, at least two or more substrates 200 may be disposed along a longitudinal direction of the body 100 inside the body 100 and spaced apart from each other in a thickness direction of the body 100.

The

coil patterns

310, 320, 330, 340, 300 may be disposed on at least one surface of at least two or more substrates 200, and preferably, are disposed on both surfaces of at least two or more substrates 200. Here, the

coil patterns

310 and 320 may be formed below and above the first substrate 210, respectively, and electrically connected through the conductive via holes formed on the first substrate 210. Similarly, the

coil patterns

330 and 340 may be formed below and above the second substrate 220, respectively, and electrically connected through conductive vias formed on the second substrate 220. This coil pattern 300 may be formed in a spiral shape in a direction from a predetermined region of the substrate 200, for example, from the central portion to the outside, and one coil may be defined in such a manner that two coil patterns formed on the substrate 200 are connected. That is, two or more coils may be formed in one body 100. Here, the

coil patterns

310 and 330 above the substrate 200 and the

coil patterns

320 and 340 below the substrate may be formed in the same shape as each other. Also, a plurality of coil patterns 300 may be formed to overlap each other, or the

lower coil patterns

320, 340 may also be formed to overlap regions where no

upper coil patterns

310, 330 are formed.

The

external electrodes

410, 420, 400 may be formed at both end portions of the body 100. For example, the external electrode 400 may be formed on two side surfaces facing each other in the longitudinal direction of the body 100. This external electrode 400 may be electrically connected to the coil pattern 300 of the body 100. That is, at least one end portion of the plurality of coil patterns 300 may be exposed to the outside of the body 100, and the external electrode 400 may be formed so as to be connected to the end portion of the plurality of coil patterns 300. For example, the coil pattern 310 may be formed to be connected to the

coil patterns

310, 330, and the coil pattern 320 may be formed to be connected to the

coil patterns

320, 340.

The connection electrode 700 may be formed on at least one side surface of the body 100 on which no external electrode 400 is formed. This connection electrode 700 is provided to connect at least one of the

coil patterns

310, 320 formed on the first substrate 210 with at least one of the

coil patterns

330, 340 formed on the second substrate 220. Accordingly, the

coil patterns

310 and 320 formed on the first substrate 210 and the

coil patterns

330 and 340 formed on the second substrate 220 may be electrically connected to each other via the connection electrode 700 outside the body 100. This connection electrode 700 may be formed at one side of the body 100 by dipping the body 100 into a conductive paste or through various methods such as printing, deposition, or sputtering. The connection electrode 700 may be formed of a metal having conductivity, for example, including one or more metals selected from the group consisting of gold, silver, platinum, copper, nickel, palladium, and alloys thereof. Here, a nickel plating layer (not shown) or a tin plating layer (not shown) may be further formed on the surface of the connection electrode 700, as necessary.

As described above, the power inductor according to the third exemplary embodiment includes at least two or more substrates 200 having the coil patterns 300 respectively formed on at least one surface thereof in the body 100, so that a plurality of coils can be formed in one body 100. Thus, the capacity of the power inductor may be increased.

Fig. 9 is a perspective view of a power inductor according to a fourth exemplary embodiment, and fig. 10 and 11 are sectional views taken along lines a-a 'and B-B' of fig. 9, respectively.

Referring to fig. 9 to 11, a power inductor according to a fourth exemplary embodiment may include: a main body 100; at least two or

more substrates

210, 220, 200 disposed inside the body 100; a

coil pattern

310, 320, 330, 340, 300 formed on at least one surface of each of the two or more substrates 200; first

external electrodes

810, 820, 800 disposed on both side surfaces of the body 100 facing each other and connected to the

coil patterns

310, 320, respectively, and second

external electrodes

910, 920, 900 disposed on both side surfaces of the body 100 facing each other and connected to the

coil patterns

330, 340, respectively, to be spaced apart from the first

external electrodes

810, 820. That is, the coil patterns 300 respectively formed on at least two or more substrates 200 are connected through the first and second external electrodes 800 and 900, respectively, which are different, so that two or more power inductors can be implemented in one body 100.

The first

external electrodes

810, 820, 800 may be formed at both end portions of the body 100. For example, the first

external electrodes

810, 820 may be formed on two side surfaces facing each other in the longitudinal direction of the body 100. The first

external electrodes

810 and 820 may be electrically connected to the

coil patterns

310 and 320 formed on the first substrate 210. That is, at least one end portions of the

coil patterns

310, 320 are exposed to the outside of the body 100 in directions facing each other, respectively, and the first

external electrodes

810, 820 may be formed so as to be connected to the end portions of the

coil patterns

310, 320. Such first

external electrodes

810, 820 may be formed at both ends of the body 100 by dipping the body 100 into a conductive paste or through various methods such as printing, deposition, and sputtering, and then patterned. Also, the first

external electrodes

810 and 820 may be formed of a metal having conductivity, such as one or more metals selected from the group consisting of gold, silver, platinum, copper, nickel, palladium, and alloys thereof. Also, a nickel plating layer (not shown) or a tin plating layer (not shown) may be further formed on the surfaces of the first

external electrodes

810, 820.

The second

external electrodes

910, 920, 900 may be formed at both end portions of the main body 100, and spaced apart from the first

external electrodes

810, 820. That is, the first and second

external electrodes

810 and 820 and 910 and 920 may be formed on the same surface of the body 100 and formed to be spaced apart from each other. The second

external electrodes

910 and 920 may be electrically connected to the

coil patterns

330 and 340 formed on the second substrate 220. That is, at least one end portions of the

coil patterns

330, 340 are exposed to the outside of the body 100 in directions facing each other, respectively, and the second

external electrodes

910, 920 may be formed so as to be connected to the end portions of the

coil patterns

330, 340. Here, although the

coil patterns

330 and 340 are exposed in the same direction as the

coil patterns

310 and 320, the coil patterns may be connected to the first and second external electrodes 800 and 900, respectively, by being exposed while not overlapping each other but being spaced apart from each other by a predetermined distance. The second

external electrodes

910 and 920 may be formed through the same process as the first

external electrodes

810 and 820. That is, the second

external electrodes

910, 920 may be formed at both ends of the body 100 by dipping the body 100 into a conductive paste or through various methods such as printing, deposition, and sputtering, and then patterned. Also, the second

external electrodes

910 and 920 may be formed of a metal having conductivity, for example, one or more metals selected from the group consisting of gold, silver, platinum, copper, nickel, palladium, and alloys thereof. Also, a nickel plating layer (not shown) or a tin plating layer (not shown) may be further formed on the surfaces of the second

external electrodes

910, 920.

Fig. 12 is a perspective view of a power inductor according to a modified exemplary embodiment of the fourth exemplary embodiment, and first

external electrodes

810 and 820 and second

external electrodes

910 and 920 are formed in different directions from each other. That is, the first and second

external electrodes

810 and 820 and 910 and 920 may be formed on the side surfaces of the body 100 perpendicular to each other. For example, the first

external electrodes

810, 820 may be formed on two side surfaces facing each other in the longitudinal direction of the body 100, and the second

external electrodes

910, 920 may be formed on two side surfaces facing each other in the lateral direction of the body 100.

Referring to fig. 13,

coil patterns

310, 320 having a predetermined shape are formed on at least one surface of the substrate 200 or preferably on one surface and the other surface of the substrate. The substrate 200 may be formed of CCL, metal ferrite, or the like, and is preferably formed of metal ferrite that can increase effective permeability and allow capacity to be easily realized. For example, the substrate 200 may be manufactured by attaching copper foil to one surface and the other surface of a metal plate having a predetermined thickness and formed of a metal alloy containing iron. Also, the

coil patterns

310, 320 may be formed as coil patterns formed in a circular spiral shape from a predetermined region of the substrate 200, for example, from a central portion. Here, after the coil pattern 310 is formed on one surface of the substrate 200, a conductive via hole penetrating a predetermined region of the substrate 200 and filled with a conductive material is formed, and the coil pattern 320 may be formed on the other surface of the substrate 200. The conductive via hole may be formed by forming a via hole in the thickness direction of the substrate 200 using a laser or the like and filling the via hole with a conductive paste. Also, the coil pattern 310 may be formed through an electroplating process. For this, a photosensitive film pattern having a predetermined shape is formed on one surface of the substrate 200. Next, an electroplating process is performed by using the copper foil on the substrate 200 as a seed, and the coil pattern may be formed by removing the photosensitive film after a metal layer is grown from the exposed surface of the substrate 200. Of course, the coil pattern 320 may be formed on the other surface of the substrate 200 through the same method used to form the coil pattern 310. The

coil patterns

310, 320 may also be formed in multiple layers. When the

coil patterns

310 and 320 are formed in multiple layers, an insulating layer is formed between upper and lower layers, and conductive vias (not shown) are formed in the insulating layer, so that the multiple layers of coil patterns can be connected. In this way, after the

coil patterns

310, 320 are formed on one surface and the other surface of the substrate 200, respectively, the insulating layer 500 is formed to cover the

coil patterns

310, 320. The insulating layer 500 may be formed by coating with an insulating polymer material such as parylene. That is, parylene may be deposited on the

coil patterns

310, 320 by providing the substrate 200 having the

coil patterns

310, 320 formed thereon inside the deposition chamber and then vaporizing and supplying parylene into the vacuum chamber. For example, a first heating process of parylene is first heated and vaporized in a vaporizer to convert to a dimer (dimer) state, and then a second heating process is heated and thermally decomposed to a Monomer (Monomer) state. When the parylene is then cooled by using a cold trap provided to connect to the decomposition chamber and a mechanical vacuum pump, the parylene transitions from a monomeric state to a polymeric state and is deposited on the

coil pattern

310, 320. Here, the first heating process for vaporizing and converting parylene into a dimer state may be performed at a temperature of approximately 100 ℃ to approximately 200 ℃ and a pressure of approximately 1.0 torr. The second heating process for thermally decomposing the vaporized parylene and converting the parylene to a monomer state may be performed at a temperature of approximately 400 ℃ to approximately 500 ℃ and a pressure of approximately 0.5 torr or higher. Also, in order to deposit parylene by converting the monomer state to the polymer state, the deposition chamber may be maintained at a room temperature of approximately 25 ℃ and a pressure of approximately 0.1 torr. In this way, the insulating layer 500 may be coated along a step in the

coil patterns

310, 320 by coating parylene on the

coil patterns

310, 320, and thus, the insulating layer 500 may be formed in a uniform thickness. Of course, the insulating layer 500 may also be formed by closely attaching a sheet including one or more materials selected from the group consisting of epoxy, polyimide, and liquid crystal polymer to the

coil patterns

310, 320.

Referring to fig. 14, a plurality of sheets 100a to 100h formed of a material including a metal powder 110, a polymer 120, and a thermally conductive filler 130 are provided. Here, a metal material containing iron (Fe) may be used for the metal powder 110. Epoxy, polyimide, or the like, which can insulate the metal powders 110 from each other, may be used for the polymer 120. MgO, AlN, a carbon-based material, or the like may be used for the thermally conductive filler 130, through which the heat of the metal powder 110 may be dissipated to the outside. Also, the surface of the metal powder 110 may be coated with a ferrite material such as metal oxide ferrite or an insulating material such as parylene. Here, the polymer 120 may be included in an amount of approximately 2.0 wt% to approximately 5.0 wt% with respect to 100 wt% of the metal powder, and the thermally conductive filler 130 may be included in an amount of approximately 0.5 wt% to approximately 3.0 wt% with respect to 100 wt% of the metal powder 110. The plurality of sheets 100a to 100h are disposed above and below a substrate 200 on which

coil patterns

310, 320 are formed, respectively. The plurality of sheets 100a to 100h may have different contents of the thermally conductive filler 130 from each other. For example, the content of the thermally conductive filler 130 may gradually increase in a direction upward or downward from one surface and the other surface of the substrate 200. That is, the content of the thermally conductive filler 130 in the

sheets

100b, 100e positioned above and below the

sheets

100a, 100d contacting the substrate 200 may be greater than the content of the thermally conductive filler 130 in the

sheets

100a, 100 d. Also, the content of the thermally conductive filler 130 in the

sheets

100c, 100f positioned above and below the

sheets

100b, 100e may be greater than the content of the thermally conductive filler 130 in the

sheets

100b, 100 e. In this way, the content of the thermally conductive filler 130 in the direction away from the substrate 200 becomes larger, and therefore, the efficiency of heat transfer can be further improved. As described in another exemplary embodiment, the first and second

magnetic layers

610 and 620 may be disposed above the uppermost sheet and below the

lowermost sheets

100a and 100h, respectively. First magnetic layer 610 and second magnetic layer 620 may be fabricated from materials having a permeability greater than lamellae 100 a-100 h. For example, the first and second

magnetic layers

610 and 620 may be manufactured by using ferrite powder and epoxy resin so as to have a magnetic permeability greater than that of the sheets 100a to 100 h. Also, it is allowable that the thermal conductive filler is further included in the first and second

magnetic layers

610 and 620.

Referring to fig. 15, the body 100 is formed such that a plurality of sheets 100a to 100h are laminated, pressed, and formed with a substrate 200 interposed therebetween. Also, the external electrodes 400 may be formed on both end portions of the body 100, so that the external electrodes may be electrically connected to the extended portions of the

coil patterns

310, 320. The external electrode 400 may be formed such that the body 100 is impregnated into a conductive paste or on both end portions of the body 100 through various methods such as printing, deposition, and sputtering of the conductive paste. Here, a metal material that may allow the external electrode 400 to have conductivity may be used as the conductive paste. Also, if necessary, a nickel plating layer and a tin plating layer may be further formed on the surface of the external electrode 400.

Fig. 16 is a sectional image of a power inductor according to a comparative example in which an insulating layer is formed of polyimide, and fig. 17 is a sectional image of a power inductor according to an exemplary embodiment in which an insulating layer is formed of parylene. As illustrated in fig. 17, although parylene is formed along the steps in the

coil patterns

310, 320 with a small thickness, polyimide is formed with a thickness greater than that of parylene, as illustrated in fig. 16. Also, in order to measure the ESD characteristics of the power inductors according to the comparative examples and the exemplary embodiments, a voltage of approximately 400 volts was repeatedly applied to the power inductors in the 20 comparative examples and the 20 embodiments, respectively, once to ten times. For the comparative example in which the insulating layer was formed of polyimide, 19 power inductors from among the 20 power inductors were short-circuited, but for the embodiment in which the insulating layer was formed of parylene, all of the 20 power inductors were not short-circuited. Also, an insulation power voltage was measured, which in the comparative example was approximately 25 volts and in the exemplary embodiment was approximately 86 volts. Accordingly, the insulating layer 500 formed of parylene for insulating the

coil patterns

310, 320 from the body 100 may be formed to have a small thickness, and insulating characteristics or the like may be improved.

This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Furthermore, the invention is to be defined solely by the scope of the following claims.

Claims

1. A power inductor, comprising:

a main body;

at least one substrate disposed inside the body;

at least one coil pattern disposed on at least one surface of the substrate; and

an insulating layer formed between the coil pattern and the body, wherein the insulating layer is formed of parylene having a thickness of 3 to 100 μm, the insulating layer having a uniform thickness along a shape of the coil pattern, parylene being thermally decomposed by being vaporized by a first heating and being cooled by a second heating to be deposited on the coil pattern.

2. The power inductor of claim 1, wherein the body comprises a metal powder, a polymer, and a thermally conductive filler.

3. The power inductor of claim 2, wherein the metal powder comprises a metal alloy powder including iron.

4. The power inductor of claim 3, wherein the metal powder has a surface coated with at least one of a ferrite material and an insulator.

5. The power inductor according to claim 4, wherein the insulator is coated with parylene at a thickness of 1 μm to 10 μm.

6. The power inductor of claim 2, wherein the thermally conductive filler comprises one or more selected from the group consisting of MgO, AlN, and carbon-based material.

7. The power inductor according to claim 6, wherein the thermally conductive filler is included in an amount of 0.5 wt% to 3 wt% with respect to 100 wt% of the metal powder, and has an average particle diameter of 0.5 μm to 100 μm.

8. The power inductor according to claim 1, wherein the substrate is formed of a copper clad laminate or formed such that copper foils are attached to both surfaces of a metal plate containing iron.

9. The power inductor according to claim 1, further comprising an external electrode formed outside the body and connected to the coil pattern.

10. The power inductor of claim 1, wherein the substrates are arranged at least in duplicate or more and the coil pattern is formed on each of at least two or more of the substrates.

11. The power inductor according to claim 10, further comprising a connection electrode disposed outside the body and provided to connect at least two or more of the coil patterns.

12. The power inductor according to claim 11, further comprising at least two or more external electrodes connected to at least two or more of the coil patterns, respectively, and formed outside the body.

13. The power inductor according to claim 12, wherein a plurality of the external electrodes are formed on the same side surface of the body to be spaced apart from each other, or are formed on side surfaces of the body different from each other.

14. The power inductor of claim 1, further comprising a magnetic layer disposed in at least one region of the body, and a magnetic permeability of the magnetic layer is greater than a magnetic permeability of the body.

15. The power inductor according to claim 14, wherein the magnetic layer is formed to include a thermally conductive filler.